WO2019093219A1

WO2019093219A1 - Heat-curable urethane resin composition, film, and article

Info

Publication number: WO2019093219A1
Application number: PCT/JP2018/040670
Authority: WO
Inventors: 大地樋口; 雄一郎柴
Original assignee: Dic株式会社
Priority date: 2017-11-07
Filing date: 2018-11-01
Publication date: 2019-05-16
Also published as: US11807754B2; KR20200070412A; US20210163738A1; JPWO2019093219A1; TW201922833A; TWI680993B; JP6705564B2; KR102381732B1

Abstract

Provided are: a heat-curable urethane resin composition excellent in terms of self-healing property, antifouling property, and elongation; a film including a cured coating film obtained from the heat-curable urethane resin composition; and an article including the film. Use is made of a heat-curable urethane resin composition which comprises a main ingredient and a hardener, the main ingredient comprising an organic solvent and a urethane prepolymer having a hydroxyl group at an end and formed from a composition comprising polyols, one or more polyisocyanates, and a chain extender, characterized in that the polyols comprise polyols which contain no aromatic ring, the polyols which contain no aromatic ring comprising a liquid polycarbonate polyol and a solid polycarbonate polyol, the polyisocyanates comprise a polyisocyanate containing no aromatic ring, and the chain extender comprises a low-molecular-weight triol, that the hardener comprises a triisocyanate, and that the total content of the low-molecular-weight triol and the triisocyanate is 10-35 mass%.

Description

Thermosetting urethane resin composition, film and article

The present invention relates to a thermosetting urethane resin composition, a film and an article using the same.

Thermosetting urethane resin compositions are currently used in various applications such as automobile parts, home electric parts, packaging materials, leather-like sheets, printing rolls and the like.

A hard coat layer has been provided on the surface of a conventional article such as a plastic member or a metal member for the purpose of preventing damage (improvement of durability) and maintaining the appearance. However, the hard coat layer is hard to be scratched, but once scratched, the scratch is not restored, dirt tends to adhere to the scratch, and contamination tends to spread from the scratch, and the aesthetic appearance of the article It was a cause of damage.

Furthermore, because of the hard and brittle nature of the hard coat layer having high hardness as described above, (1) the surface is likely to be cracked or scratched over a long period of use, and (2) the scratch once attached to the surface is restored (3) When the base material to be coated is a soft material such as polycarbonate, high hardness of the target level is not expressed, and durability in the outermost layer can not be ensured. There was a problem with that.

Therefore, in recent years, a thermosetting resin composition having a function (hereinafter, referred to as "self-repairing property") in which a scratch once attached to the surface recovers spontaneously has been proposed. (For example, refer to patent documents 1 and 2.). Such a self-healing thermosetting resin composition is soft and elastic, and can recover to its original state after several seconds to several minutes even if a dent such as an abrasion is once attached, There is an advantage that the initial good scratch resistance can be maintained.

However, the thermosetting resin composition having the conventional self-repairing property is excellent in the self-repairing property and the antifouling property, but has a problem that the elongation is small and the processability as a decorative film is not sufficient.

Then, the thermosetting resin composition which has self-repairing property, antifouling property, and can form the coating film excellent in elongation was calculated | required.

Japanese Patent Laid-Open No. 2-74540 JP, 2016-147416, A

Problems to be solved by the present invention include a thermosetting urethane resin composition excellent in self-healing property, antifouling property and elongation, a film having a cured coating film of the thermosetting urethane resin composition, and the film Providing an article having the

As a result of earnest studies to solve the above problems, the present inventors formed a composition containing a polyol having no aromatic ring containing a specific polyol, a polyisocyanate having no aromatic ring and a specific chain extender. The present invention has been found that the above problems can be solved by using a thermosetting urethane resin composition containing a base material containing an organic solvent and a prepolymer having a hydroxyl group at one end and a curing agent. I did.

That is, the present invention is based on a composition comprising a polyol (a1), a polyisocyanate (a2) and a chain extender (a3) and containing a urethane prepolymer (A) having a hydroxyl group at an end and an organic solvent (B). A thermosetting urethane resin composition comprising (i) and a curing agent (ii), wherein the polyol (a1) comprises a polyol (a1-1) containing no aromatic ring, and the aroma The ring-free polyol (a1-1) comprises a polycarbonate polyol which is liquid at 25 ° C. and a polycarbonate polyol which is solid at 25 ° C., and the polyisocyanate (a2) is a poly not having an aromatic ring. It contains isocyanate (a2-1), and the chain extender (a3) contains triol having a molecular weight of 500 or less. The curing agent (ii) contains triisocyanate, and in the thermosetting urethane resin composition (in the component forming the thermosetting urethane resin composition), the triol having the molecular weight of 500 or less and the triol. A thermosetting urethane resin composition characterized in that the total content with triisocyanate is 10% by mass to 35% by mass, a film having the cured coating film thereof, and an article using the film It is.

Since the thermosetting urethane resin composition of the present invention can form a film having a coating film excellent in self-healing property, antifouling property and elongation, it can be used, for example, in automobiles, home appliances, mobile phones, OA equipment, and automobiles. It can be suitably used for applications such as decorative films used for parts of the above, and plastic coating.

The thermosetting urethane resin composition of the present invention comprises a urethane prepolymer (A) formed from a composition containing a polyol (a1), a polyisocyanate (a2) and a chain extender (a3) and an organic solvent (B) Containing main agent (i) and curing agent (ii). In addition, the "main ingredient" as used in the field of this invention refers to a composition which exceeds 50 mass% to the total amount of a composition. In other words, the content of the curing agent (ii) is less than 50% by mass in the thermosetting urethane resin composition of the present invention.

The urethane prepolymer (A) has a hydroxyl group at the molecular terminal, and preferably does not contain an aromatic ring. The urethane prepolymer (A) may be obtained by mixing all of the polyol (a1) and the chain extender (a3) and the polyisocyanate (a2) at one time, and the polyol (a1) and the chain may be obtained. Obtained by mixing at least a part of the extender (a3) with the polyisocyanate (a2) and then mixing the obtained prepolymer with the remainder of the polyol (a1) and the chain extender (a3) It may be In particular, after mixing at least a part of the polyol (a1) (preferably the solid polycarbonate polyol described later) and the chain extender (a3) and the polyisocyanate (a2), the obtained prepolymer and the polyol (a1) are obtained. It is preferable that it is a thing obtained by mixing with the remainder (preferably liquid polycarbonate polyol mentioned later). The urethane prepolymer (A) and the prepolymer may contain unreacted polyol (a1) and / or polyisocyanate (a2).

The polyol (a1) contains a polyol (a1-1) containing no aromatic ring, and the polyol (a1-1) containing no aromatic ring contains a polycarbonate polyol containing no aromatic ring.

As polycarbonate polyol which does not contain the above-mentioned aromatic ring, it may only be called "alicyclic" that it is aliphatic polycarbonate polyol and polycarbonate polyol which has alicyclic structure (Hereafter, it is what has alicyclic structure. And aliphatic polycarbonate polyols are preferred. As said aliphatic or alicyclic polycarbonate polyol, what is obtained by carrying out the esterification reaction of carbonic acid and aliphatic or alicyclic carbonate ester, and an aliphatic or alicyclic polyhydric alcohol is mentioned, for example. Examples of the aliphatic or alicyclic carbonate include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate and the like. Moreover, as the aliphatic or alicyclic polyhydric alcohol, for example, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether Examples include glycol, 1,4-cyclohexanedimethanol and the like. One or two or more of these polycarbonate polyols can be used.

The polycarbonate polyol containing no aromatic ring is a polycarbonate polyol which is liquid at 25 ° C. (hereinafter sometimes simply referred to as “liquid polycarbonate polyol”) and a polycarbonate polyol which is solid at 25 ° C. (hereinafter, simply “solid polycarbonate polyol” May be included.

The liquid polycarbonate polyol may be a liquid at 25 ° C., may be an amorphous or crystalline polycarbonate polyol, and is preferably an amorphous polycarbonate polyol. The number of hydroxyl groups contained in the liquid polycarbonate polyol is preferably 2.

The viscosity of the liquid polycarbonate polyol is preferably 10,000 mPa · s or less, more preferably 7,000 mPa · s or less, still more preferably 5,000 mPa · s or less at room temperature (25 ° C.), for example 100 mPa · s. The above, preferably 500 mPa · s or more.

The number average molecular weight of the liquid polycarbonate polyol is preferably more than 500, more preferably 600 or more, still more preferably 700 or more, preferably less than 2,000, more preferably 1,800 or less, still more preferably 1,500. It is below.

The glass transition temperature of the liquid polycarbonate polyol is preferably -100 ° C. or more, more preferably -90 ° C. or more, still more preferably -80 ° C. or more, particularly preferably -75 ° C. or more, preferably -5 ° C. or less. More preferably, it is −15 ° C. or less, still more preferably −25 ° C. or less, and particularly preferably −35 ° C. or less.

The content of the liquid polycarbonate polyol is preferably 25% by mass or more, more preferably 30% by mass or more, in the thermosetting urethane resin composition (in the component forming the thermosetting urethane resin composition). Preferably it is 50 mass% or less, More preferably, it is 45 mass% or less.

The solid polycarbonate polyol means a polycarbonate polyol which is solid at 25 ° C., and it may be a crystalline polycarbonate polyol having a crystallization temperature of more than 25 ° C. The number of hydroxyl groups contained in the solid polycarbonate polyol is preferably 2.

The crystallization temperature of the solid polycarbonate polyol is preferably 30 ° C. or more, more preferably 35 ° C. or more, still more preferably 40 ° C. or more, preferably 100 ° C. or less, more preferably 80 ° C. or less, still more preferably 70 It is less than ° C.

In the polycarbonate polyol containing no aromatic ring, the content of the liquid polycarbonate polyol is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 35% by mass or more, preferably 80% by mass or less. More preferably, it is 70 mass% or less, More preferably, it is 65 mass% or less. When the content of the liquid polycarbonate polyol is in the above range, the self-repairing property, the antifouling property and the elongation can be easily improved.

The content rate of the polycarbonate polyol not containing an aromatic ring is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass in the total of the polyol (a1). % By mass or more, particularly preferably 99% by mass or more, and the upper limit is 100% by mass.

In addition, as the polyol (a1-1) containing no aromatic ring, if necessary, a polyol containing no aromatic ring, such as a polyester polyol containing no aromatic ring, a polyether polyol containing no aromatic ring (preferably (Aliphatic or alicyclic polyol) can be used in combination.

As polyester polyol which does not contain the above-mentioned aromatic ring, aliphatic or alicyclic polyester polyol is mentioned, and aliphatic polyester polyol is preferred. Examples of the polyester polyol include polyester polyols obtained by reacting low molecular weight polyols with polycarboxylic acids; polyester polyols obtained by ring-opening polymerization reaction of cyclic ester compounds such as ε-caprolactone; The polyester polyol etc. which are obtained by superposition | polymerization are mentioned. One or two or more of these polyester polyols can be used.

Examples of the low molecular weight polyol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, and 1,2-butane. Diol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3 -Propanediol, neopentyl glycol, 2-b 2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, glycerin, trimethylo- Aliphatic polyols such as propane, ditrimethylolpropane, trimethylolpropane and pentaerythritol, and alicyclic polyols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A.

As the polycarboxylic acid, those having no aromatic ring can be used, and for example, aliphatic polycarboxylic acids such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, dimer acid, etc. And alicyclic polycarboxylic acids such as 1,4-cyclohexanedicarboxylic acid and cyclohexanetricarboxylic acid.

Examples of the aromatic ring-free polyether polyols include aliphatic or alicyclic polyether polyols, with aliphatic polyether polyols being preferred. As said polyether polyol, the polytetramethylene glycol obtained by the ring-opening polymerization of tetrahydrofuran is mentioned, for example. Moreover, what carried out addition polymerization of the alkylene oxide is mentioned as a 1 type (s) or 2 or more types of compound which has 2 or more of active hydrogen atoms as an initiator. Examples of the compound having two or more active hydrogen atoms include propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin and di- Glycerin, trimethylolethane, trimethylolpropane, water, hexanetriol and the like can be mentioned. Moreover, as said alkylene oxide, a propylene oxide, a butylene oxide, a styrene oxide, epichlorohydrin, tetrahydrofuran etc. are mentioned, for example. One or two or more of these polyether polyols can be used.

The polyol (a1) may contain a polyol (a1-2) containing an aromatic ring, as long as the effect of the present invention is not impaired. The content of the polyol (a1-2) containing an aromatic ring is preferably 30% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, still more preferably 5% by mass in the polyol (a1). The content is at most mass%, particularly preferably at most 1 mass%, and the lower limit is 0 mass%.

The number average molecular weight of the polyol (a1) is preferably more than 500, more preferably 600 or more, still more preferably 700 or more, preferably 10,000 or less, more preferably 5,000 or less, still more preferably 4, It is less than 000.
In the present specification, the number average molecular weight of the polyol (a1) represents a converted value obtained by using gel permeation chromatography (GPC) using polystyrene as a standard sample.

Examples of the aromatic ring-free polyisocyanate (a2) include alicyclic polyisocyanates such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, etc. And aliphatic polyisocyanates. Among these, it is preferable to use hexamethylene diisocyanate from the viewpoints of self-repairing property, antifouling property and elongation of the obtained coating film. Moreover, 1 type or 2 types or more can be used for these polyisocyanate (a2).

The chain extender (a3) contains a low molecular weight triol having a molecular weight of 500 or less. The molecular weight of the low molecular weight triol is preferably 300 or less, more preferably 250 or less. The molecular weight of the chain extender (a3) can be calculated based on a chemical formula.

The low molecular weight triol has three hydroxyl groups, and, for example, glycerin; trimethylolmethane, trimethylolethane, trimethylolpropane, trimethylolbutane and the like, and three methylol groups (hydroxymethyl groups) each having 1 carbon atom Compounds bonded to a terminal carbon atom of a linear alkane of ~ 4; 1,2,5-hexanetriol; oxyalkylene adducts of trimethylolpropane (2 to 4 carbon atoms, preferably oxyethylene adducts), etc. Can be mentioned. One or more low molecular weight triols can be used. Further, in the oxyalkylene adduct (preferably oxyethylene adduct) of trimethylolpropane, the addition mole number of the oxyalkylene (preferably oxyethylene) is not particularly limited, but it is 6 per one molecule of trimethylolpropane. It is preferably less than molar. Among these, three methylol groups (hydroxymethyl groups) are attached to the terminal carbon atom of the linear alkane having 1 to 4 carbon atoms from the viewpoint of self-repairing property, antifouling property and elongation of the resulting coating film. Compounds attached are preferred, and trimethylolpropane is more preferred.

As the chain extender (a3), ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene other than the low molecular weight triol Glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol 2,5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol 2-Methyl-1,3-propanediol, neopentyl Recall, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, Aliphatic polyols such as glycerin, trimethylolpropane, ditrimethylolpropane, trimethylolpropane, pentaerythritol and the like, polyols having an aliphatic cyclic structure such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A can be used in combination .

The molecular weight of the chain extender (a3) is preferably 500 or less, more preferably 300 or less, and still more preferably 250 or less.

In the chain extender (a3), the content of the low molecular weight triol is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and the upper limit is 100% by mass. .

The content of the chain extender (a3) is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, based on 100 parts by mass of the total amount of the urethane prepolymer. The amount is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 36 parts by mass or less.

The hydroxyl group equivalent of the urethane prepolymer (A) is preferably 400 g / eq. Or more, more preferably 450 g / eq. Or more, preferably 4000 g / eq. Or less, more preferably 3000 g / eq. It is below.

The thermosetting urethane resin composition of the present invention may contain a urethane prepolymer other than the urethane prepolymer (A). In the thermosetting urethane resin composition of the present invention, the content of the urethane prepolymer (A) in the total amount of the urethane prepolymer is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass It is the above and an upper limit is 100 mass%.

The content of the urethane prepolymer (A) is preferably 60% by mass or more, more preferably 65% by mass or more, still more preferably 60% by mass or more, in the non-volatile component of the thermosetting urethane resin composition. Is 99% by mass or less, more preferably 96% by mass or less. The nonvolatile content of the thermosetting urethane resin composition means the total amount of the thermosetting urethane resin composition excluding the organic solvent.

Examples of the organic solvent (B) include ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone and acetylacetone; ether solvents such as tetrahydrofuran and dioxane; ester solvents such as ethyl acetate and butyl acetate; nitrile solvents such as acetonitrile; Amide solvents such as N-methyl pyrrolidone and the like can be mentioned. One or two or more of these organic solvents can be used.

The content of the organic solvent (B) is preferably 30% by mass or more, more preferably 40% by mass or more, in the thermosetting urethane resin composition (in the component forming the thermosetting urethane resin composition). More preferably, it is 50% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 65% by mass or less.

The curing agent (ii) contains triisocyanate. The said triisocyanate can react with the hydroxyl group which the urethane prepolymer (A) in main ingredient (i) has.

The triisocyanate is a compound having three isocyanate groups, and examples thereof include an isocyanurate of diisocyanate, a trimethylolpropane adduct of diisocyanate and the like, and an isocyanurate of diisocyanate is preferable. Examples of the diisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate, and alicyclic diisocyanates such as isophorone diisocyanate. Among these, an isocyanurate of aliphatic diisocyanate is preferable, and an isocyanurate of hexamethylene diisocyanate is more preferable, from the viewpoints of self-repairing property, antifouling property and elongation of the resulting coating film. One or two or more of these isocyanate compounds can be used.

Moreover, as said hardening | curing agent (ii), other isocyanate compounds other than the said triisocyanate can be used together as needed.

Examples of the other isocyanate compounds include polyisocyanates having an alicyclic structure such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate and isophorone diisocyanate; and aliphatics such as hexamethylene diisocyanate, lysine diisocyanate, xylylene diisocyanate and tetramethyl xylylene diisocyanate. Polyisocyanate and the like can be mentioned.

In the curing agent (ii), the content of the triisocyanate is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and the upper limit is 100% by mass.

The content of the curing agent (ii) is less than 50% by mass, preferably 40% by mass or less, in the thermosetting urethane resin composition (in the component forming the thermosetting urethane resin composition). The content is preferably 30% by mass or less, more preferably 20% by mass or less, and the lower limit is, for example, 0.1% by mass.

In the thermosetting urethane resin composition of the present invention, for example, the main agent (i) and the curing agent (ii) are charged in separate tanks of a two-liquid mixing and casting machine, and the main agent (i) and the above The curing agent (ii) can be produced by mixing them with a mixing and casting machine at normal temperature.

The equivalent ratio (NCO / OH) of the isocyanate group (NCO) of the curing agent (ii) to the hydroxyl group (OH) of the main agent (i) is preferably 0.8 or more, more preferably 0.9 or more, Preferably it is 1.5 or less, More preferably, it is 1.2 or less. By the said equivalence ratio being in the said range, it becomes easy to make elongation of the coating film obtained favorable.

The total content of the low molecular weight triol and the triisocyanate is preferably 10% by mass or more, more preferably 10% by mass or more, in the thermosetting urethane resin composition (in the component forming the thermosetting urethane resin composition). It is 15% by mass or more, preferably 35% by mass or less, more preferably 30% by mass or less. By being in the above-mentioned range, the self-repairing property, the antifouling property and the elongation of the obtained coating film can be easily improved.

In addition, the thermosetting urethane resin composition of the present invention may contain an additive, if necessary, as long as the effects of the present invention are not impaired. Examples of the additive include tackifiers, leveling agents, catalysts, plasticizers, stabilizers, fillers, pigments, dyes, flame retardants, and the like.

Examples of the tackifier include rosin resins, rosin ester resins, hydrogenated rosin ester resins, terpene resins, terpene phenol resins, hydrogenated terpene resins, and C5 aliphatic resins as petroleum resins. And C9 aromatic resins, and C5 and C9 copolymer resins, etc. can be used.

Examples of the leveling agent include silicone compounds, acetylene diol compounds, and fluorine compounds.

Examples of the catalyst include tertiary amine catalysts, organometallic catalysts, and the like.

Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, diisooctyl phthalate, diisodecyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, trioctyl phosphate, epoxy plasticizers, toluene-sulfoamide, chloroparaffin, adipine Acid esters, castor oil and the like can be used. Examples thereof include methyl acid phosphate (AP-1), acrylic surface conditioner (BYK-361N) and the like.

Examples of the stabilizer include hindered phenol compounds, benzotriazole compounds and hindered amine compounds.

Examples of the filler include silicic acid derivatives, talc, metal powder, calcium carbonate, clay, carbon black and the like.

The film of the present invention has a cured coating film of the thermosetting urethane resin composition on a substrate.

Examples of the base include polyethylene terephthalate (PET), polyvinyl chloride (PVC), thermoplastic urethane (TPU), thermosetting urethane (TSU) and the like.

As a method for producing the film of the present invention, for example, the thermosetting urethane resin composition is applied to the surface of a substrate by a slit coater method such as curtain flow coater method or die coater method, knife coater method, roll coater method or the like. After coating and drying if necessary, a method of heating and curing may be mentioned. The drying may be natural drying at normal temperature, but may be heat drying. It is preferable that the heating and drying be performed usually at 40 to 250 ° C. for about 1 to 1000 seconds. In the secondary curing step, heating and drying may be performed at 40 to 100 ° C. for about 1 to 24 hours.

The thermosetting urethane resin composition of the present invention is, for example, a galvanized steel plate used for automobiles, home appliances, mobile phones, office automation equipment, automobile parts, etc., a plated steel plate such as an aluminum-zinc alloy steel plate, an aluminum plate It can be used suitably for uses, such as metal base materials, such as aluminum alloy plate, an electromagnetic steel plate, a copper plate, and a stainless steel plate.

Hereinafter, the present invention will be specifically described by examples and comparative examples.

Preparation Example 1 Preparation of Main Agent (1)
100 parts by weight of methyl ethyl ketone and 100 parts by weight of ethyl acetate in a 1-liter four-necked round-bottom flask equipped with a nitrogen inlet tube, thermometer, and stirrer 50 parts by weight of Etanacor UH-200 (manufactured by Ube Industries, Ltd.) and 5 parts by weight of trimethylolpropane were added and stirred. Subsequently, 13 parts by mass of hexamethylene diisocyanate and 0.02 parts by mass of dibutyltin dilaurate were added. After raising the internal temperature to 70 ° C. while paying attention to heat generation, the mixture was stirred while maintaining the temperature, and 50 parts by mass of liquid polycarbonate diol (Duranol G3452, manufactured by Asahi Kasei Corporation) was further added, and stirring was continued. Stirring continuation time after temperature rising to 70 ° C. was 4 hours. A main agent (i) containing a urethane prepolymer having a hydroxyl equivalent of 2205 and having a hydroxyl group at a molecular end was obtained.

Preparation Examples 2 to 12: Preparation of Main Agents (ii) to (xii)
Main agent having a hydroxyl group at the molecular end in the same manner as in Preparation Example 1 except that the type and amount of the polyol and polyisocyanate used, the crosslinking agent, and the equivalent weight of the hydroxyl group of the obtained prepolymer are changed as shown in Tables 1 and 2. (Ii) to (xii) were obtained.
In the table, Etanacol UM-90 represents liquid polycarbonate diol (Etanacor UM-90, manufactured by Ube Industries, Ltd.), and hydrogenated MDI represents hydrogenated diphenylmethane diisocyanate.

[Low temperature solution stability of main agent]
The obtained main agent was allowed to stand in a temperature-controlled room at 0 ° C. for 3 days, the appearance was visually confirmed, and the resin which was white and had no sedimentation was evaluated as excellent in a clear solution state.

(Example 1: Production of Hardener)
100 parts by weight of the main agent (i) obtained in Preparation Example 1 and 2.9 parts by weight of polyisocyanate (hexamethylene diisocyanate nurate body, Burnoc 902S, manufactured by DIC), leveling agent (Silclean 3700, manufactured by Big Chemie Japan) 0 .3 parts by weight were mixed to obtain a thermosetting urethane resin composition as a urethane resin coating liquid. The coating solution was coated on a polyethylene terephthalate film subjected to release treatment with a knife coater to a thickness of 30 μm and further heated in an oven at 110 ° C. for 2 minutes for primary curing to obtain a predetermined film.

(Examples 2 to 6, Comparative Examples 1 to 6)
A predetermined film was obtained in the same manner as in Example 1 except that the types and amounts of the main agent and polyisocyanate used, and as shown in Tables 1 and 2, were changed.
In the table, Dezmodule W represents dicyclohexylmethane-4,4'-diisocyanate.

Tables 1-2 show hydroxyl equivalent of urethane prepolymer contained in main agents (i) to (xii), liquid polycarbonate polyol in thermosetting urethane resin composition (component to form the thermosetting urethane resin composition) The content shows the total content of triol having a molecular weight of 500 or less and the above triisocyanate.

The following evaluation was performed using the film obtained by said Example and comparative example.

[Method of evaluating coatability]
The surface of the film produced by heat curing was observed visually, and those which were flat without repelling or unevenness were evaluated as ○, and those which were not usable practically as a coating material due to repelling or unevenness were evaluated as x.

[Evaluation method of tack]
Those with no tackiness were evaluated as ○, and those without tackiness were evaluated as x. ×: There is tackiness. .

[Stain resistance evaluation method]
A line was drawn on the film with Magic (PENTEL PEN, black, middle character), and the ease of wiping when wiped with a tissue paper was evaluated as follows ◎: The magic is completely removed in 5 wipes ○: The magic is completely removed in 10 wipes Δ: The magic is not partially removed in 10 wipes.
X: Magic is hardly removed after 10 wipes

[Method of evaluating self-healing ability]
After pressing a brass brush on the film with a load of 500 g against the film and moving it back and forth 10 times, the presence or absence of scratches was visually confirmed and evaluated as follows.
: 1: Wounds recovered within 1 minute :: Wounds recovered within 10 minutes 回復: Wounds recovered within 1 hour ×: Wounds not recovered even after 1 hour

[Evaluation method of elongation]
The film was cut into a strip having a width of 1 cm and a length of 5 cm, and the film was pulled using "Autograph AG-I" manufactured by Shimadzu Corporation, and the elongation (elongation) was measured.
:: 200% or more :: 100% or more and less than 200% :: 150% or more and less than 180% ×: less than 100%

Examples 1 to 6 are films formed from the thermosetting urethane resin composition of the present invention, having self-repairing property, antifouling property, and good elongation.

Comparative Examples 1 and 4 have a low total content of low molecular weight triol and triisocyanate, Comparative Example 2 has a high total content of low molecular weight triol and triisocyanate, and Comparative Example 3 has a liquid polycarbonate polyol Comparative Example 4 does not contain a triisocyanate as a crosslinking agent, Comparative Example 5 does not contain a triol as a chain extender, Comparative Example 6 does not contain a solid polycarbonate polyol, and all of them are self-healing And the antifouling property and the elongation were not compatible.

Claims

Main agent (i) formed from a composition containing a polyol (a1), a polyisocyanate (a2) and a chain extender (a3) and having a hydroxyl group at the end and a urethane prepolymer (A) and an organic solvent (B) A thermosetting urethane resin composition containing an agent (ii),
The polyol (a1) contains a polyol (a1-1) not containing an aromatic ring,
The aromatic ring-free polyol (a1-1) comprises a polycarbonate polyol liquid at 25 ° C. and a polycarbonate polyol solid at 25 ° C.,
The polyisocyanate (a2) contains a polyisocyanate (a2-1) not containing an aromatic ring,
The chain extender (a3) contains a triol having a molecular weight of 500 or less,
The curing agent (ii) contains triisocyanate,
In the thermosetting urethane resin composition, the total content of triol having a molecular weight of 500 or less and the triisocyanate is 10% by mass or more and 35% by mass or less. .
2. The thermosetting urethane resin composition according to claim 1, wherein the content of the polycarbonate polyol liquid at 25 ° C. in the thermosetting urethane resin composition is 25 mass% or more and 50 mass% or less.
The thermosetting urethane resin composition according to claim 1 or 2, wherein the triol having a molecular weight of 500 or less is trimethylolpropane.
The thermosetting urethane resin composition according to any one of claims 1 to 3, wherein the triisocyanate is an isocyanurate of hexamethylene diisocyanate.
A film having a cured coating film of the thermosetting urethane resin composition according to any one of claims 1 to 4.
An article comprising the film according to claim 5.